The invention relates to a method for determining a fault in an electronically commutated electric motor, in which in every motor phase at least one stator coil of the electric motor is connected in parallel, with a motor phase being energized, and the current flowing through this motor phase being measured.
A method for checking the phases of an electronically commutated electric motor is known from DE 10 2011 083 217 A1. In this electric motor to be checked the respectively two coils arranged in each motor phase of the electric motor are connected serially. In order to reliably detect any phase interruption, successively at least two commutation steps of the electric motor are initiated, and a current measurement is performed in each commutation step. If here in one motor phase a power outage is detected, an interruption of the motor phase is concluded.
However, there are also electric motors in which the two coils are connected in parallel in the respective motor phase. Here, in case of a fault of such a coil connected in parallel a current flow still occurs. The electric motor still runs thereby, however with reduced capacity. If this defective electric motor is operated like a functioning one, severe consequential damages may arise in the electric motor.